Overhead door construction



Dec. 27, 1938. J. E; 'CASSE 2,141,515

OVERHEAD DOOR C ONS TRUC'II ON 1 Filed May a. 1957 2 Sheets-Sheet 1 Dgc. 27, 1938. CASSE 2,141,515

OVERHEAD DOOR CONSTRUCTION Filed May 8, 1937 2 She ets-Sheet 2 Patented Dec. 27, 1 938 UNITED STATES riot:

OVERHEAD DOOR CONSTRUCTION Application May 8, 1937, Serial No. 141,471

3 Claims.

This invention relates to door constructions of the type wherein a door is moved from a vertical closed position to an overhead substantially horizontal position,

5 More specifically the invention is concerned with the counterbalancing of overhead doors with weights less than the weights of the doors.

- The door constructions of this invention include a system of vertical and horizontal tracks with the vertical tracks mounted adjacent the sides of the door frame and the horizontal tracks extending inwardly from the door frame. Rollers are provided at the upper ends of the door for engaging with the tracks. Another pair of rollers is mountedon thedoor below the center of mass thereof but abovethe bottomof the door for engaging with the vertical tracks. is thus adapted to be swung outwardly and .raised'from a closed vertical position to a. sub go stantially horizontal overhead position. Since I the door is pivoted to the vertical tracks about the rollers carried below the center of mass of the door increasing proportions of the weight of the door are borne by the horizontal tracks as the door is opened.

Counterweights act against the door below the center of mass thereof preferably at the points where the lower pair of rollers are mounted. Since these counterweights are utilized for facilitating the opening and closing of the door it is desirable that they be arranged so as to require little effort for moving the door from opened or closed position and yet at the same time hold the door in open position and permit the weight of the door to hold itself in closed position.

According to this invention the door is pivoted about a pair of rollers which are below the center of mass of the door or below the transverse axis of balance of the door. This makes possible the use of counterweights weighing less than the weight of the door for balancing the door since,

as the door is swung open, part of its weight is borne by the horizontal tracks and the weights need not be sufiiciently heavy to support the entire door for holding the same in opened position. At the same time since the weights are less than the weight of the door, the door will close the bottom-of the door but below its center of mass, the proportion of the weight of the door so borne on the horizontal tracks can be regulated The door so that a major portion of the weight of the counterweights is necessary to hold the door open. Thus when closing the door from an open position, the operator only need exert a downward. pull of small magnitude to start raising the 6 counterweights. This pull decreases to zero as soon as the door comes down in the vertical tracks a sufiicient distance so that the proportion of its weight acting on the counterweights equals the weight of the counterweights. From then on 10 the door closes by gravity. The invention therefore deals with the positioning of vertically movable pivots for doors of the overhead type and the counterbalancing of the doors with weights weighing less than the weights of the doors, to- 15 gether with a. regulation of the pivot positions and weights of the counterweigh'ts so that little manual force is necessary for operating the doors.

It is thenan object of this invention to balance doors of the overhead type with counterweights 20 weighing less than the weight of the door.

A further object of this invention is to provide an overhead door construction wherein increasing amounts of the weight of the door are borne by the overhead track as the door is opened.

A further object of this invention is to provide, in an overhead door construction, a pivotal mounting for the door below the center of mass thereof together with counterweights acting on 30 a gravity. 40

Other and further objects of this invention will become apparent to those skilled in the art ing in which the door is mounted. I

Figure 2 is a vertical cross-sectional view taken substantially along the line 1I--II of Figural and showing in dotted lines various positions of the door and counterweights therefor as the'door" is opened from a closed position.

.Figure 3 is a cross-sectional view, with parts in 66 ure 1. a

Figure 4 is a cross-sectional view, with parts in elevation, taken along the line IVIV of Figure 1.

The invention has been illustrated in connection with a one-piece overhead garage door but it should be understood that the invention is not limited for use with garage doors alone since the same may be utilized for various other forms of unhinged doors that are opened by'an upward sliding movement.

As shown on the drawings:

In Figures 1 and 2, the reference numeral 23 designates a garage door having side edges M fitting freely between door jarnbs i2 at the bottom thereof and side edges it fitting behind the door jambs 32 as best shown in Figure 3. Plates not shown) can be used to Weatherstrip the bottom part of the door for sealing any space between the edges ii and the door jamb l2.

The door jarnb i2 defines a doorway Hi which the door i3 is adapted to close. The doorway it gives entrance to a garage having a ceiling it as shown in Figure 2.

The door it! carries on the inside top corners thereof brackets i6 having axles ii extending outwardly therefrom in back of the door jambs l2. As best shown in Figure 3, the axles I! are preferably locked against rotation as by a pin it seated in the strap it.

Rollers l9 are rotatably mounted on the ends of the axles i7.

The door i3 also carries at the sides thereof below its center of mass or below its transverse axis of balance, additional straps2li supporting axles 2i extending outwardly in back of the door jambs l2 for receiving in rotatable relation on the ends thereof rollers 22 as best shown in Figure 4. The axles 2! are preferably locked against rotation by a locking pin 23 inserted through each strap 20. An eye or hook 23 extends upwardly from each axle H as best shown in Figure 4 for a purpose to be hereinafter described.

L-shaped tracks 25 of U-shaped cross-section have vertical legs 26 mounted on the insides of the door jambs I2 in spaced relation from the door jambs on the bottom brackets 2! which are securely bolted or riveted to the vertical legs of the tracks and to the door jamb l2 as bestshown in Figure 2. Horizontal legs 28 of the tracks 25, as best shown in Figure 2, are suspended beneath the ceiling l5 of the garage by means of straps such as 29. Brackets 30 are secured to the tracks 25 at the intersection of the vertical and horizontal legs 26 and 28 thereof. The brackets 30 are securely bolted to the door jarnbs l2 above the I door I0.

The rollers l9 and 22 are engageable in the tracks 25 with the rollers l3 adapted to be rolled out of the vertical legs 26 of the tracks and back along the horizontal legs 28as best shown in Figure 2. The rollers 22 remain in the vertical legs.

26 of the tracks.

As best shown in Figure 3, each bracket 30 hasv the upper corner 3| thereof bent inwardly above yoke portion 32 and is of sumciently large diameter to extend over the axles l'l carried by the door. The sheave 33 is rotatably mounted on an axle 34 .extending'through the yoke portion 32 of the bracket.

Flexible means such as chains, cables or ropes 35 are secured at one end thereof to the eyes 24 carried on the axles 2i and are disposed around the sheaves 33. The other ends of the cables or ropes 35 are secured to counterweights 36 on each side of the door. The sheaves 33 are preferably .grooved for receiving the cables 35 and are angularly disposed above the tracks so that one side of each sheave is directly above an eye 24 of an axle 2| while the other side of each sheave is outside of a horizontal leg 28 of the tracks thereby providing unobstructed vertical paths for the cables.

As best shown in Figure 2, the door ii! is moved from a vertical closed position shown in solid lines to a substantially'horizontal position as shown in dotted lines by raising the door Iii until the rollers I9 at the top thereof are free to slide in the horizontal legs 28 of the tracks. The bottom of the door is then swung outwardly about the rollers 22 as pivots. The counterweights 33 counterbalance the weight of the door. however, are less than the weight of the door so that the door will remain in closed position by action of gravity. However as the door is moved upwardly and outwardly, increasing portions of the weight of the door are borne by the horizontal tracks 28 by virtue of the rollers i9 resting on these tracks and because of the pivot rollers 22 being below the center of mass or transverse axis of balance of the door it]. Therefore, as soon as the weight of the door not supported in the horizontal tracks 28 becomes less than the weight of the counterweights, the door will open automatically and will be held in opened position by the counterweights.

As an example of the counterbalancing feature of this invention, if a 100 1b. door, 8 feet high, has

the rollers 22 mounted below the center of mass of the door, say at 3 feet from the bottom of the door, there will be 5 feet of door above the rollers. Ifv counterweights totaling'90 'lbs. are used for counterbalancing the door and act through cable and pulley arrangements such as illustrated on the drawings with the ends of the cables secured at the rollers 22, it is obvious that in closed vertical position of the door the door is 10 lbs. heavier than the weights. Therefore a 10 lb. force is necessary to move the door upward and outward for initiating an opening of the door. During the outward swinging of the bottom of the door,

however, the rollers i9 at the top of the door bear on the horizontal tracks 28 so that part of the weight of the door is supported by these tracks.

With thelOO lb. door in exact balance in horizontal position, the proportion of the weight of the door supported by the horizontal tracks can be termed .m-lbs. The proportion of the weight of the door supported by the counterweights will then be 100 lbs. minus :r-lbs. In solving for a: with the moment arms acting on the 8 foot door since. it is known that the center of mass of the door is 4 feet from the base of the door; that the counterweights act on the door at 3 feet from the base of the door and; that the tracks act on the door at 8 feet from the base of the door, the following equation is obtained:

3 (100 minus 3:) plus'8x=400.

51::100. 1:20. It is thus obvious that 20 lbs. of the door are supported by the horizontal tracks when the door is in open horizontal position and that 100 minus 20 or lbs. of the door is allthat need be supported by the counterweights. However, the counterweights weigh lbs. and therefore 10 From the above it is obvious that 10 lbs. of

the counterweights operates to maintain the door in either opened or closed position and that a manual force of 10 lbs. is all that is necessary to overcome the equilbrium established in either opened or closed position.

I am aware that many changes may be made and numerous details of construction may be varied through a wide range without departing from the principles of this invention, and I,

therefore, do not purpose limiting the patent granted hereon otherwise than necessitated by the prior art.

I claim as my invention:

1. In a door construction having a door, means for mounting said door for movement from a substantially vertical closed position to a substantially horizontal overhead position including vertical and horizontal tracks on each side of the door, and a roller on each side of the door at the top thereof engageable with the vertical and horizontal tracks, the improvement which comprises a roller on each side of the door below the transverse axis of balance of the door but spaced from the bottom of the door engageable with the vertical tracks, sheaves above the top of the door at each side thereof, flexible means disposed over said sheaves secured at one end to the door adjacent the lower pair of rollers and counterweights slightly lighter than the weight of the door secured to the other ends of said flexible means whereby the .door remains closed by gravity but as it is moved from a closed to an opened position, increasing portions of the weight of the door are borne by the horizontal tracks and the door is held open by the counterweights and whereby substantially equal added forces of small magnitude only are required to move the door from openor closed positions.

2. In a door construction having a door, means for mounting said door for movement from a vertical closed position to a substantially horizontal overhead position including vertical and horizontal tracks on each side of the door, counterweights less than the weight of the door acting on the door to lift the same, and a roller mounted on each. -side of the door at the top thereof engageable with the horizontal tracks,

the improvement which comprises a roller engageable with the vertical tracks mounted on 'each side of the door below the center of mass of the door but above the bottom of the door to transfer increasing portions of the weight of the door to the horizontal tracks as the door is opened until the fully opened door has a portion of its weight supported on the horizontal tracks that is greater than the weight represented by the difference in weight of the unsupported door and the counterweights whereby when the door.

is in vertical closed position, its weight will overbalance the counterweights and the door will remain closed, and when the door is in opened horizontal position, the counterweights will overbalance the'weight of the door to hold the door open while substantially equal applied forces are operative to move said door from closed or opened position.

3. In a door construction having a door, means formounting saiddoor for movement from a vertical closed position to a substantially horizontal overhead position including vertical and horizontal tracks on each side of the door,-and aroller mounted on each side of the door at the top thereof engageable with the horizontal tracks, the improvements which comprise pivots mounted on each side of the door for engagement with the vertical tracks, counterweights slightly less than the weight of the door acting on the door to lift the same adjacent the pivots, said pivots being mounted on the door below the center of mass of the door but above the bottom of the door to transfer increasing portions of the weight of the door to the horizontal tracks as the door is opened until the fully opened door has a portion of its weightsupported on the horizontal tracks that is equivalent to twice the amount of the weight represented by the differ ence' in weight of the unsupported door and the counterweights whereby, when the door is in closed vertical position, its own weight will overbaiance the counterweights and the door will re-, .main closed and when the door .is in opened horizontal position, the counterweights will overbalance the weight of vthe door to hold the door open while substantially the same applied forces of small magnitude are operative to move the door from either closed or opened position.

JOSEPH E. CASBE. 

